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Security Controls and Defense

📖 2 min read

Defense in Depth

Security is not a single wall—it's a series of barriers where the failure of one layer does not compromise the entire system.

Layered Security Strategy

  1. Physical Layer: Facilities, hardware protection
  2. Perimeter Layer: Firewalls, intrusion prevention
  3. Network Layer: Segmentation, monitoring
  4. Host Layer: Endpoint protection, patch management
  5. Application Layer: Secure coding, WAF
  6. Data Layer: Encryption, access controls
  7. User Layer: Training, behavior monitoring

Zero Trust Architecture

Core Principles

  • Never Trust, Always Verify: Authenticate and authorize every request
  • Assume Breach: Design for compromise scenarios
  • Principle of Least Privilege: Minimal necessary access
  • Microsegmentation: Granular network controls

Implementation Components

  • Identity Verification: Multi-factor authentication (MFA)
  • Device Security: Endpoint detection and response (EDR)
  • Network Security: Software-defined perimeters
  • Application Security: API security, secure coding
  • Data Protection: Classification, encryption
  • Analytics: User behavior analytics (UBA)

Access Control Models

RBAC (Role-Based)

  • Structure: Users → Roles → Permissions
  • Benefits: Simplified administration, consistent policies
  • Challenges: Role explosion, rigid structure
  • Best Practices: Regular role reviews, separation of duties

Best for: Organizations with stable, well-defined roles

ABAC (Attribute-Based)

  • Components: Subject, Object, Action, Environment
  • Benefits: Fine-grained control, dynamic policies
  • Challenges: Complex implementation, policy management
  • Context-aware: Time, location, device attributes

Best for: Complex, dynamic access requirements

Mandatory Access Control (MAC)

  • Characteristics: System-enforced security labels
  • Use Cases: Government, military, high-security environments
  • Examples: SELinux, classified information systems

Encryption and Cryptography

Symmetric Encryption

When to Use Symmetric Encryption

Use symmetric encryption (like AES) for bulk data encryption where both parties can securely share the key. It's significantly faster than asymmetric encryption and ideal for encrypting large data volumes at rest or in transit.

  • Characteristics: Same key for encryption and decryption
  • Algorithms:
    • AES (Advanced Encryption Standard): Industry standard
    • ChaCha20: Modern stream cipher
    • Legacy: 3DES (deprecated), Blowfish
  • Use Cases: Bulk data encryption, disk encryption
  • Key Management: Secure distribution and storage challenge

Asymmetric Encryption

When to Use Asymmetric Encryption

Use asymmetric encryption (like RSA or ECC) for key exchange, digital signatures, and scenarios where parties cannot securely share a symmetric key. The public key can be distributed freely while the private key remains secret.

  • Characteristics: Public/private key pairs
  • Algorithms:
    • RSA: Widely used, key sizes 2048+ bits
    • Elliptic Curve (ECC): Smaller keys, equivalent security
    • Post-Quantum: Preparing for quantum computing threats
  • Use Cases: Key exchange, digital signatures, SSL/TLS

Hash Functions and Digital Signatures

  • Secure Hash Algorithms:
    • SHA-2: SHA-256, SHA-512 (current standard)
    • SHA-3: Latest NIST standard
    • Avoid: MD5, SHA-1 (cryptographically broken)
  • Digital Signatures: Non-repudiation, integrity verification
  • Certificate Authorities: Public Key Infrastructure (PKI)

Modern Security Technologies

Artificial Intelligence and Machine Learning

  • Applications:
    • Threat Detection: Anomaly detection, behavioral analysis
    • Incident Response: Automated analysis and containment
    • Vulnerability Assessment: Code analysis, configuration review
  • Challenges:
    • False Positives: Balancing sensitivity and accuracy
    • Adversarial ML: Attacks against AI systems
    • Data Quality: Training on representative datasets

Extended Detection and Response (XDR)

  • Evolution: EDR → MDR → XDR
  • Capabilities: Unified threat detection across multiple vectors
  • Components: Endpoint, network, email, cloud, identity
  • Benefits: Correlated analysis, reduced alert fatigue

Security Orchestration, Automation, and Response (SOAR)

  • Purpose: Automate routine security tasks
  • Components: Playbooks, case management, threat intelligence
  • Benefits: Faster response times, consistent procedures
  • Implementation: Integration with existing security tools

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